#pragma once

#ifndef TCG_TRIANGULATE_HPP

#define TCG_TRIANGULATE_HPP

// tcg includes

#include "../triangulate.h"

#include "../traits.h"

#include "../point_ops.h"

// OS-specific includes

#if defined(_WIN32)

#include "windows.h"

#include <gl glu.h=""></gl>

#elif defined(MACOSX)

#include <glut glut.h=""></glut>

#elif defined(LINUX)

#include <gl glut.h=""></gl>

#include <cstring></cstring>

#endif

#ifndef TCG_GLU_CALLBACK

#ifdef WIN32

#define TCG_GLU_CALLBACK void(CALLBACK *)()

#else

#define TCG_GLU_CALLBACK void (*)()

#endif

#endif

#ifndef CALLBACK

#define CALLBACK

#endif

namespace tcg {

//**************************************************************************************

//    GLU Tessellator Callbacks

//**************************************************************************************

namespace detail {

template <typename mesh_type=""></typename>

struct CBackData {

  mesh_type *m_mesh;

  int m_triangle[3];

  int m_i;

};

//============================================================================

// NOTE: must be declared with CALLBACK directive

template <typename mesh_type=""></typename>

void CALLBACK tessBegin(GLenum type, void *polygon_data) {

  assert(type == GL_TRIANGLES);

  CBackData<mesh_type> *data = (CBackData<mesh_type> *)polygon_data;</mesh_type></mesh_type>

  data->m_i                  = 0;

}

//----------------------------------------------------------------------------

template <typename mesh_type=""></typename>

void CALLBACK tessEnd(void *polygon_data) {

  CBackData<mesh_type> *data = (CBackData<mesh_type> *)polygon_data;</mesh_type></mesh_type>

  assert(data->m_i == 0);

}

//----------------------------------------------------------------------------

template <typename mesh_type,="" typename="" vertex_type=""></typename>

void CALLBACK tessVertex(void *vertex_data, void *polygon_data) {

  typedef typename mesh_type::vertex_type::point_type point_type;

  CBackData<mesh_type> *data = (CBackData<mesh_type> *)polygon_data;</mesh_type></mesh_type>

  vertex_type *vData         = (vertex_type *)vertex_data;

  GLdouble(&pos)[3] =

      TriMeshStuff::glu_vertex_traits<vertex_type>::vertex3d(*vData);</vertex_type>

  int &idx = TriMeshStuff::glu_vertex_traits<vertex_type>::index(*vData);</vertex_type>

  if (idx < 0) {

    data->m_mesh->addVertex(

        typename mesh_type::vertex_type(point_type(pos[0], pos[1])));

    idx = data->m_mesh->verticesCount() - 1;

  }

  data->m_triangle[data->m_i] = idx;

  data->m_i                   = (data->m_i + 1) % 3;

  if (data->m_i == 0)

    data->m_mesh->addFace(data->m_triangle[0], data->m_triangle[1],

                          data->m_triangle[2]);

}

//----------------------------------------------------------------------------

// Supplied to ensure that triangle primitives are always of type GL_TRIANGLE

template <typename mesh_type=""></typename>

void CALLBACK edgeFlag(GLboolean flag) {}

}  // namespace tcg::detail

//**************************************************************************************

//    Polygon triangulation

//**************************************************************************************

namespace detail {

template <typename func=""></typename>

void gluRegister(GLUtesselator *tess, GLenum which, Func *func) {

  gluTessCallback(tess, which, (TCG_GLU_CALLBACK)func);

}

}  // namespace tcg::detail

//---------------------------------------------------------------------------

template <typename containersreader="" forit,="" typename=""></typename>

void gluTriangulate(ForIt tribeBegin, ForIt tribeEnd,

                    ContainersReader &meshes_reader) {

  using namespace detail;

  typedef typename tcg::traits<typename forit::value_type="">::pointed_type</typename>

      family_type;

  typedef typename tcg::traits<typename family_type::value_type="">::pointed_type</typename>

      polygon_type;

  typedef typename polygon_type::value_type vertex_type;

  typedef typename tcg::container_reader_traits<containersreader> output;</containersreader>

  typedef

      typename tcg::traits<typename output::value_type="">::pointed_type mesh_type;</typename>

  GLUtesselator *tess = gluNewTess();  // create a tessellator

  assert(tess);

  // Declare callbacks

  // NOTE: On g++, it seems that at this point each of the callbacks still have

  // undefined type.

  // We use the above gluRegister template to force the compiler to generate

  // these types.

  gluRegister(tess, GLU_TESS_BEGIN_DATA, tessBegin<mesh_type>);</mesh_type>

  gluRegister(tess, GLU_TESS_END_DATA, tessEnd<mesh_type>);</mesh_type>

  gluRegister(tess, GLU_TESS_VERTEX_DATA, tessVertex<mesh_type, vertex_type="">);</mesh_type,>

  gluRegister(tess, GLU_TESS_EDGE_FLAG, edgeFlag<mesh_type>);</mesh_type>

  output::openContainer(meshes_reader);

  // Iterate the tribe. For every polygons family, associate one output mesh

  for (ForIt it = tribeBegin; it != tribeEnd; ++it) {

    // Build the output mesh and initialize stuff

    mesh_type *mesh = new mesh_type;

    CBackData<mesh_type> cbData;  // Callback Data about the mesh</mesh_type>

    cbData.m_mesh = mesh;

    // Tessellate the family

    gluTessBeginPolygon(tess, (void *)&cbData);

    typename family_type::iterator ft, fEnd = (*it)->end();

    for (ft = (*it)->begin(); ft != fEnd; ++ft) {

      gluTessBeginContour(tess);

      typename polygon_type::iterator pt, pEnd = (*ft)->end();

      for (pt = (*ft)->begin(); pt != pEnd; ++pt)

        gluTessVertex(

            tess, TriMeshStuff::glu_vertex_traits<vertex_type>::vertex3d(*pt),</vertex_type>

            (void *)&*pt);

      gluTessEndContour(tess);

    }

    gluTessEndPolygon(tess);  // Invokes the family tessellation

    output::addElement(meshes_reader, mesh);

  }

  gluDeleteTess(tess);  // delete after tessellation

  output::closeContainer(meshes_reader);

}

//**************************************************************************************

//    Mesh refinement

//**************************************************************************************

namespace detail {

template <typename mesh_type=""></typename>

inline void touchEdge(std::vector<uchar> &buildEdge, mesh_type &mesh, int e) {</uchar>

  typename mesh_type::edge_type &ed = mesh.edge(e);

  int f1 = ed.face(0), f2 = ed.face(1);

  if (f1 >= 0) {

    typename mesh_type::face_type &f = mesh.face(f1);

    buildEdge[f.edge(0)] = 1, buildEdge[f.edge(1)] = 1,

    buildEdge[f.edge(2)] = 1;

  }

  if (f2 >= 0) {

    typename mesh_type::face_type &f = mesh.face(f2);

    buildEdge[f.edge(0)] = 1, buildEdge[f.edge(1)] = 1,

    buildEdge[f.edge(2)] = 1;

  }

}

//---------------------------------------------------------------------------

template <typename mesh_type=""></typename>

inline void touchVertex(std::vector<uchar> &buildEdge, mesh_type &mesh, int v) {</uchar>

  // Sign all adjacent edges and adjacent faces' edges to v

  typename mesh_type::vertex_type &vx = mesh.vertex(v);

  const tcg::list<int> &incidentEdges = vx.edges();</int>

  tcg::list<int>::const_iterator it;</int>

  for (it = incidentEdges.begin(); it != incidentEdges.end(); ++it)

    touchEdge(buildEdge, mesh, *it);

}

//================================================================================

template <typename mesh_type=""></typename>

class BoundaryEdges {

  std::vector<uchar> m_boundaryVertices;</uchar>

  const mesh_type &m_mesh;

public:

  BoundaryEdges(const mesh_type &mesh) : m_mesh(mesh) {

    const tcg::list<typename mesh_type::edge_type=""> &edges = mesh.edges();</typename>

    const tcg::list<typename mesh_type::vertex_type=""> &vertices =</typename>

        mesh.vertices();

    m_boundaryVertices.resize(vertices.nodesCount(), 0);

    typename tcg::list<typename mesh_type::edge_type="">::const_iterator it;</typename>

    for (it = edges.begin(); it != edges.end(); ++it) {

      if (it->face(0) < 0 || it->face(1) < 0) {

        m_boundaryVertices[it->vertex(0)] = true;

        m_boundaryVertices[it->vertex(1)] = true;

      }

    }

  }

  ~BoundaryEdges() {}

  void setBoundaryVertex(int v) {

    m_boundaryVertices.resize(m_mesh.vertices().nodesCount(), 0);

    m_boundaryVertices[v] = 1;

  }

  bool isBoundaryVertex(int v) const {

    return v < int(m_boundaryVertices.size()) && m_boundaryVertices[v];

  }

  bool isBoundaryEdge(int e) const {

    const typename mesh_type::edge_type &ed = m_mesh.edge(e);

    return ed.face(0) < 0 || ed.face(1) < 0;

  }

};

}  // namespace tcg::detail

//=============================================================================

template <typename mesh_type=""></typename>

void TriMeshStuff::DefaultEvaluator<mesh_type>::actionSort(</mesh_type>

    const mesh_type &mesh, int e,

    typename ActionEvaluator<mesh_type>::Action *actionSequence) {</mesh_type>

  typedef ActionEvaluator<mesh_type> ActionEvaluator;</mesh_type>

  int count = 0;

  memset(actionSequence, ActionEvaluator::NONE,

         3 * sizeof(typename ActionEvaluator::Action));

  // Try to minimize the edge length deviation in e's neighbourhood

  const typename mesh_type::edge_type &ed = mesh.edge(e);

  int f1 = ed.face(0), f2 = ed.face(1);

  const TPointD *v1, *v2, *v3, *v4;

  double length[6];

  v1 = &mesh.vertex(ed.vertex(0)).P();

  v2 = &mesh.vertex(ed.vertex(1)).P();

  length[0]        = norm(*v2 - *v1);

  double lengthMax = length[0], lengthMin = length[0];

  if (f1 >= 0) {

    v3        = &mesh.vertex(mesh.otherFaceVertex(f1, e)).P();

    length[1] = norm(*v3 - *v1);

    length[2] = norm(*v3 - *v2);

    lengthMax = std::max({lengthMax, length[1], length[2]});

    lengthMin = std::min({lengthMin, length[1], length[2]});

  }

  if (f2 >= 0) {

    v4        = &mesh.vertex(mesh.otherFaceVertex(f2, e)).P();

    length[3] = norm(*v4 - *v1);

    length[4] = norm(*v4 - *v2);

    lengthMax = std::max({lengthMax, length[3], length[4]});

    lengthMin = std::min({lengthMin, length[3], length[4]});

  }

  if (f1 >= 0 && f2 >= 0) {

    // Build the edge lengths

    length[5] = norm(*v4 - *v3);

    // Evaluate swap - take the triangles with least maximum mean boundary edge

    double m1 = (length[0] + length[1] + length[2]) / 3.0;

    double m2 = (length[0] + length[3] + length[4]) / 3.0;

    double m3 = (length[5] + length[1] + length[3]) / 3.0;

    double m4 = (length[5] + length[2] + length[4]) / 3.0;

    if (std::max(m3, m4) < std::max(m1, m2) - 1e-5)

      actionSequence[count++] = ActionEvaluator::SWAP;

    // NOTE: The original swap evaluation was about maximizing the minimal face

    // angle.

    // However, this requires quite some cross products - the above test is

    // sufficiently

    // simple and has a similar behaviour.

    // Evaluate collapse

    if (length[0] < m_collapseValue)

      actionSequence[count++] = ActionEvaluator::COLLAPSE;

  }

  // Evaluate split

  if (length[0] > m_splitValue)

    actionSequence[count++] = ActionEvaluator::SPLIT;

}

//=============================================================================

namespace detail {

template <typename mesh_type=""></typename>

inline bool testSwap(const mesh_type &mesh, int e) {

  // Retrieve adjacent faces

  const typename mesh_type::edge_type &ed = mesh.edge(e);

  int f1 = ed.face(0), f2 = ed.face(1);

  if (f1 < 0 || f2 < 0) return false;

  // Retrieve the 4 adjacent vertices

  const typename mesh_type::vertex_type &v1 = mesh.vertex(ed.vertex(0));

  const typename mesh_type::vertex_type &v2 = mesh.vertex(ed.vertex(1));

  const typename mesh_type::vertex_type &v3 =

      mesh.vertex(mesh.otherFaceVertex(f1, ed.getIndex()));

  const typename mesh_type::vertex_type &v4 =

      mesh.vertex(mesh.otherFaceVertex(f2, ed.getIndex()));

  // Make sure that vertex v4 lies between the semiplane generated by v3v1 and

  // v3v2

  TPointD a(v1.P() - v3.P()), b(v2.P() - v3.P());

  double normA = norm(a), normB = norm(b);

  if (normA < 1e-5 || normB < 1e-5) return false;

  a = a * (1.0 / normA);

  b = b * (1.0 / normB);

  TPointD c(v4.P() - v1.P()), d(v4.P() - v2.P());

  double normC = norm(c), normD = norm(d);

  if (normC < 1e-5 || normD < 1e-5) return false;

  c = c * (1.0 / normC);

  d = d * (1.0 / normD);

  double crossAC = point_ops::cross(a, c);

  int signAC     = crossAC < -1e-5 ? -1 : crossAC > 1e-5 ? 1 : 0;

  double crossBD = point_ops::cross(b, d);

  int signBD     = crossBD < -1e-5 ? -1 : crossBD > 1e-5 ? 1 : 0;

  return signAC == -signBD;

}

//----------------------------------------------------------------------------

// Tests edge e for admissibility of ad edge collapse. Edge e must not have

// adjacent

// faces with boundary components.

// Furthermore, we must test that faces adjacent to f1 and f2 keep e on the same

// side of

// the line passing through v3v1 and v3v2.

template <typename mesh_type=""></typename>

inline bool testCollapse(const mesh_type &mesh, int e,

                         const BoundaryEdges<mesh_type> &boundary) {</mesh_type>

  // Any face adjacent to e must have no boundary edge

  const typename mesh_type::edge_type &ed = mesh.edge(e);

  int f1 = ed.face(0), f2 = ed.face(1);

  if (f1 < 0 || f2 < 0) return false;

  int v1 = mesh.edge(e).vertex(0), v2 = mesh.edge(e).vertex(1);

  if (boundary.isBoundaryVertex(v1) || boundary.isBoundaryVertex(v2))

    return false;

  // Test faces adjacent to v1 or v2. Since one of their vertices will change,

  // we must make sure that their

  //'side' does not change too.

  int v = mesh.otherFaceVertex(f1, e);

  int l = mesh.edgeInciding(v1, v);

  int f =

      mesh.edge(l).face(0) == f1 ? mesh.edge(l).face(1) : mesh.edge(l).face(0);

  int vNext = mesh.otherFaceVertex(f, l);

  while (f != f2) {

    // Test face f

    if (tsign(point_ops::cross(mesh.vertex(vNext).P() - mesh.vertex(v).P(),

                               mesh.vertex(v2).P() - mesh.vertex(v).P())) !=

        tsign(point_ops::cross(mesh.vertex(vNext).P() - mesh.vertex(v).P(),

                               mesh.vertex(v1).P() - mesh.vertex(v).P())))

      return false;

    // Update vars

    v = vNext;

    l = mesh.edgeInciding(v1, v);

    f = mesh.edge(l).face(0) == f ? mesh.edge(l).face(1) : mesh.edge(l).face(0);

    vNext = mesh.otherFaceVertex(f, l);

  }

  // Same with respect to v2

  v = mesh.otherFaceVertex(f1, e);

  l = mesh.edgeInciding(v2, v);

  f = mesh.edge(l).face(0) == f1 ? mesh.edge(l).face(1) : mesh.edge(l).face(0);

  vNext = mesh.otherFaceVertex(f, l);

  while (f != f2) {

    // Test face f

    if (tsign(point_ops::cross(mesh.vertex(vNext).P() - mesh.vertex(v).P(),

                               mesh.vertex(v2).P() - mesh.vertex(v).P())) !=

        tsign(point_ops::cross(mesh.vertex(vNext).P() - mesh.vertex(v).P(),

                               mesh.vertex(v1).P() - mesh.vertex(v).P())))

      return false;

    // Update vars

    v = vNext;

    l = mesh.edgeInciding(v2, v);

    f = mesh.edge(l).face(0) == f ? mesh.edge(l).face(1) : mesh.edge(l).face(0);

    vNext = mesh.otherFaceVertex(f, l);

  }

  return true;

}

}  // namespace tcg::detail

//----------------------------------------------------------------------------

template <typename mesh_type=""></typename>

void refineMesh(mesh_type &mesh, TriMeshStuff::ActionEvaluator<mesh_type> &eval,</mesh_type>

                unsigned long maxActions) {

  using namespace detail;

  typedef TriMeshStuff::ActionEvaluator<mesh_type> Evaluator;</mesh_type>

  typedef typename Evaluator::Action Action;

  // DIAGNOSTICS_TIMER("simplifyMesh");

  // Build boundary edges. They will not be altered by the simplification

  // procedure.

  detail::BoundaryEdges<mesh_type> boundary(mesh);</mesh_type>

  Action actions[3], *act, *actEnd = actions + 3;

  tcg::list<edge> &edges = mesh.edges();</edge>

  tcg::list<edge>::iterator it;</edge>

  // DIAGNOSTICS_SET("Simplify | Vertex count (before simplify)",

  // mesh.vertexCount());

  // DIAGNOSTICS_SET("Simplify | Edges count (before simplify)", edges.size());

  // Build a vector of the edges to be analyzed

  std::vector<uchar> buildEdge(edges.nodesCount(), 1);</uchar>

  int touchedIdx;

  bool boundaryEdge;

cycle:

  if (maxActions-- == 0) return;

  // Analyze mesh for possible updates. Perform the first one.

  for (it = edges.begin(); it != edges.end(); ++it) {

    if (!buildEdge[it.m_idx]) continue;

    boundaryEdge = boundary.isBoundaryEdge(it.m_idx);

    eval.actionSort(mesh, it.m_idx, actions);

    for (act = actions; act < actEnd; ++act) {

      // Try to perform the i-th action

      if (*act == Evaluator::NONE)

        break;

      else if (!boundaryEdge && *act == Evaluator::SWAP &&

               testSwap(mesh, it.m_idx)) {

        touchedIdx = mesh.swapEdge(it.m_idx);

        touchEdge(buildEdge, mesh, touchedIdx);

        goto cycle;

      } else if (!boundaryEdge && *act == Evaluator::COLLAPSE &&

                 testCollapse(mesh, it.m_idx, boundary)) {

        touchedIdx = mesh.collapseEdge(it.m_idx);

        touchVertex(buildEdge, mesh, touchedIdx);

        goto cycle;

      } else if (*act == Evaluator::SPLIT) {

        Edge &ed = mesh.edge(it.m_idx);

        touchVertex(buildEdge, mesh, ed.vertex(0));

        touchVertex(buildEdge, mesh, ed.vertex(1));

        touchedIdx = mesh.splitEdge(it.m_idx);

        if (buildEdge.size() < edges.size()) buildEdge.resize(edges.size());

        touchVertex(buildEdge, mesh, touchedIdx);

        if (boundaryEdge) boundary.setBoundaryVertex(touchedIdx);

        goto cycle;

      }

    }

    buildEdge[it.m_idx] = 0;

  }

  // DIAGNOSTICS_SET("Simplify | Vertex count (after simplify)",

  // mesh.vertexCount());

  // DIAGNOSTICS_SET("Simplify | Edges count (after simplify)", edges.size());

}

}  // namespace tcg

#endif  // TCG_TRIANGULATE_HPP